The DNA Sequencing Core Facility is a shared facility used by over 50 laboratories doing cancer-related research. The full resources of the Facility are utilized by accepting reactions from the entire University and some outside institutions, which have lower priorities. The Facility provides primarily complete DNA sequencing of plasmid, PCR and large templates, such as BAC's, PAC's and cosmids, but also accepts user-generated reaction products. The reactions done by the Facility are needed for verification of plasmid constructs, identification of mutations and polymorphisms, and gene discovery. Results are provided online via the internet or the University's internal network usually within one to two days of sample submission. Reactions that are less than satisfactory are repeated at no extra charge. The Facility offers technical consultations for DNA preparation and data interpretation.